وَ تَصْدِيقُ ذَلِكَ مَا رَوَاهُ أَحْمَدُ بْنُ مُحَمَّدِ بْنِ عِيسَى عَنْ عَبْدِ اَلْعَزِيزِ بْنِ اَلْمُهْتَدِي عَنْ سَعِيدِ بْنِ سَعْدٍ قَالَ : سَأَلْتُهُ يَعْنِي أَبَا اَلْحَسَنِ اَلرِّضَا عَلَيْهِ اَلسَّلاَمُ عَنْ رَجُلٍ كَانَ لَهُ اِبْنٌ يَدَّعِيهِ فَنَفَاهُ وَ أَخْرَجَهُ مِنَ اَلْمِيرَاثِ وَ أَنَا وَصِيُّهُ فَكَيْفَ أَصْنَعُ فَقَالَ عَلَيْهِ اَلسَّلاَمُ "لَزِمَهُ اَلْوَلَدُ لِإِقْرَارِهِ بِالْمَشْهَدِ لاَ يَدْفَعْهُ اَلْوَصِيُّ عَنْ شَيْءٍ قَدْ عَلِمَهُ".
English translationBab Ul Qaim Publications
Hadith.5516 - And the confirmation of this is what was narrated by Ahmad ibn Muhammad ibn Isa from Abdul Aziz ibn Al-Muhtadi from Sa'id ibn Sa'd, who said: 'I asked Imam (as) - meaning Abu Al-Hasan Imam Ali ibn Musa Ar-Ridha (as) - about a man who had a son whom he acknowledged and then later disowned, excluding him from the inheritance. I am his executor, so what should I do?' Imam (as) said: "The son remains legally his due to his prior public acknowledgment. The executor cannot deny him anything that is already known."
Translation: Bab Ul Qaim Publications·Thaqalayn link·The Arabic above is the original.